The Extensible Markup Language (XML) is designed to store and transmit data. The XML can use the natural language and employ the American Standard Code for Information Interchange (ASCII) code for encoding. Any information can define its format and be expressed through the XML syntax. The XML is a platform-independent language. When data is transmitted between systems of different architectures, a standard mode is required. The XML achieves the object and at the same time does not rely on equipments and systems. When data is interchanged by using the XML, data is not lost due to different formats used by different systems. The advantage of the XML is that it can be used to share data and be applied to various applicable models, for example, Call Control XML (CCXML), Voice XML (VXML), and Simple Object Access Protocol (SOAP). Currently, the XML-based applications become increasingly wider. The messages requested by the users to be sent are generally expressed through the XML in the network.
According to some characteristics of web services and distributed XML applications, XML routers are complements to IP routers and become increasingly more meaningful in routing XML data. The existing XML router knows the type of the XML only by parsing the content of the message body of XML document and conveys it to a suitable node in the network.
The XML does not have a header, so that the type of the XML is known only by parsing the message body of the XML document. The distribution efficiency is very low, which brings some difficulties to the distributed application and deployment of the XML.